FERROELECTRIC PHASE-TRANSITION IN BATIO3 FILMS

Films of BaTiO3 single crystals with the thicknesses of 100 angstrom, 1000 angstrom and 4000 angstrom were grown on Pt/MgO (Pt for electric nodes, MgO for substrates) by means of the activated reactive evaporat ion technique. X-ray diffraction patterns were measured to clarify pro perties such as the temperature dependence of lattice parameters. It w as found that the temperature dependences of lattice parameters and in tegrated intensities of Bragg reflections showed different behavior wh ich depends on the film thickness. The relative dielectric constant ep silon(r) and remnant polarization P(r) were measured in order to inves tigate the dielectric properties of the films. Film crystals of BaTiO3 with the thickness of 4000 angstrom showed phase transitions differen t from these in the bulk state because of the effect of the substrate.